↵a The cleavage positions were determined based on a previous report (9).

↵b Mutations correlated with the attenuation are shown in lightface characters without underlining; mutations responsible for the overattenuation are shown in boldface characters without underlining; mutations might also contribute to the overattenuation are shown in lightface characters with underlining; two reversion mutations (aa 1136 in nsp10 and aa 168 in ORF2) that are probably not correlated with the attenuation or overattenuation of JXA1 are shown in boldface characters with underlining.